Electric toaster



Aug. 25, 1953 R. H. SMITH ELECTRIC TOASTER 2 Sheets-Sheet 1 Filed May 31, 1952 INVENTOR. Ric/Z 0:112 [1. 5m LZ/z ATTORNEY.

Aug. 25, 1953 R. H. SMITH ELECTRIC TOASTER 2 Sheets-Sheet 2 Filed May 31, 1952 VEIYTOR. Haifa/21f A! (smut/L Patented Aug. 25, 1953 ELECTRIC TOASTER Richard H. Smith, Canton, Ohio, assignor to The Hoover Company, North Canton, Ohio, a corporation of Ohio Application May 31, 1952, Serial No. 291,039

18 Claims.

This invention relates to toasters and more particularly to a timing mechanism therefor.

According to the present invention the power unit for the timer is a constant speed electric or other motor which operates through a special gearing arrangement to actuate a carriage release mechanism to terminate toasting intervals.

According to the broadest aspects of the present invention the gearing is engaged by movement of the bread carriage to toasting position and disengaged when the bread carriage is returned to receiving position. The constant speed power source may be controlled by movement of the bread carriage to and from toasting position or it may be separately controlled since in any event the gearing between the power source and the latch releasing mechanism is controlled by such movement of the bread carriage.

When toasters are operated repeatedly in rapid succession the toaster gets hotter and hotter until a point of equilibrium is reached. As a result, if the timed intervals are of the same duration for each toasting interval, and the timed interval is set properly for timing the first interval, starting with a cold toaster, for intervals after the first, the toast is overdone. It has therefore been necessary to successively shorten the timed intervals after the first until a condition of equilibrium is reached.

It has been proposed to vary the timed intervals by a thermal element responsive to toaster temperature so that the timed interval will be proper regardless of how soon a toasting operation is initiated after a previous one.

According to the present invention the gear ratio between a constant speed power unit and the latch release mechanism is varied by a thermal element responsive to toaster temperature. The arrangement is such that the ratio may be varied by infinitesimal increments depending upon the change in toaster temperature during or between toasting intervals. The arrangement is such that the thermal element comes into play during each toasting period including the first.

Specifically, according to the present invention, a curved cone transmission drum is utilized to transmit motion from a constant speed power source to the latch release mechanism. The cone is pivoted to move in the arc of a circle and the longitudinal curve of its surface is an arc of the same circle. A thermally responsive element is arranged to move the cone responsive to toaster temperature. During toasting intervals the surface of the cone is constantly in frictional contact with a small friction gear driven by the constant speed motor. As the toaster temperature rises the cone is moved so that the friction gear contacts the surface of the cone nearer its apex and thus increases the speed of rotation of the cone and shortens the duration of toasting intervals as the toaster heats up. At the end of each toasting interval the cone is moved away from the friction gear and at the initiation of toasting intervals the cone is returned into contact with the friction gear.

The thermally responsive element is also manually adjustable. An adjustable support is provided for the thermally responsive element to further determine the axial point on the cones surface which will be contacted by the friction gear. The adjustment is for the purpose of adjusting the timer for making various colors of toast.

Other objects and advantages of the invention will become apparent as the description proceeds when taken in connection with the accompanying drawings in which:

Figure 1 is a perspective View of the toaster of this invention with the front of the toaster broken away to show the details of the timing mechanism;

Figure 2 is a sectional view of the toaster of Fig. 1 showing the timing mechanism in plan view; and

Figure 3 is a view similar to Fig. 1 showing a variation of the way in which the cone is made to start rotation from a fixed point for each toasting interval.

Referring to the drawings, the reference numeral I0 represents the base of the toaster which may be made of any suitable insulating heat resistant material such as hard rubber or bakelite.

An appearance housing I l is supported on a ledge I2 of base I0 and is provided with bread receiving slots I3. A bottom plate I 4 is supported on a ledge l5 of base In and forms the support for the entire mechanism housed within the appearance housing I I. The interior of the appearance housing II is divided into a toasting oven and a mechanism compartment by a dividing plate I6.

A carriage plate I! is mounted for vertical reciprocation in a manner well known in the art by guide posts I8 supported at their lower ends on plate l4 and at their upper ends on a bracket l9 secured to the dividing plate I6. The carriage plate I? cazries bread carriers positioned in the S toasting oven beneath the slots l3 and between main heaters 20.

Lugs 2| extend laterally to either side of the carriage ll. Links 22 are pivoted to the lugs 2i at their lower ends and to actuating arms 23 at their upper ends. At their rear ends the arms 23 are pivoted to the walls of the toasting oven and at their forward ends are extended through a slot in the front of the appearance housing H for manual manipulation in a manner well known in the art. Downward movement of the arms 23 will move the carriage ll andbread carriers downward to toasting position against the bias of spring 24, anchored at its upper end to bracket [9 and at its lower end to the carriage The carriage ll is latched, in its downward position by a hook 25 on latch lever 26 pivoted at 21 to a bracket 28 supported from the dividing plate IE. The latch lever 25 is spring biased clockwise to latching position against a stop 29 by a spring 30. Above the hook 225 of latch lever 25 is; a cam surface 3! which, in the modification of; Fig. 3; is engaged by a lug 32 carried by one of the arms 23 when the latter are moved downwardly. When the arms '23 are moved downwardly the lever 26, is pivoted counterclockwise tOI permit the lug 32 to move below the hook 25 at which time the spring 35 returns the hook 25 to latching position.

A bracket 45 is attached to the dividing plate It near the top ofthe latter; Pivoted at one e d to the bracket 40 at M and normally springbiased counterclockwise against a stop 42* by sprin at is a lever arm M. The lever arm it; is moved clockwise against the bias of spring ,3 by a rod t pivoted to the end 45 of the lever 44 at its upper end and having a hooked lower end 41 which engages beneath an outwardly struck portion 43 on one of the lugs 21 when the arms 2 3 are moved to lowered position. The rod 45 is guided by a guide 69 attached to the dividing plate l5 so that its lower hooked end 4] will always be below the member 58. The rod 45 is coiled into a spring at 5:9 for a purpose which will appear hereinafter. I I I Pivoted to the arm A l intermediate its ends at5l is the upper end of an angle shaped arm52. The arm 52is. normally spring-biased clockwise against a stop 54 on arm 54 by a spring 53. At

its lower end the arm52 carries a spindle 56 on which a convex cone 55 is mounted for rotation. In. the modification of Figs. 1 and 2 alight spring 55" is provided for holding the cone 55 in a fixed position when it is not being driven. v

The surface of the cone 55 is longitudinally curved in the arc of a circle as shown by the dot-dash arc A A' (Fig. 2) the, center of Which is the pivot point 5! for the arm 52; v w

n enw eed le Q Q T. 31 its reductiongea'r hausing 5i is mounted on the plate H} by a suitable bracket 52. A rotatable shaft 53 extends from the upper rear side of the housing 6! and carries a small friction gear 54 of rubber or other suitable friction material, which contacts the arc-shaped surface" of the cone 55 when the carriage it is in its" downward position regardless of the pivoted position of the arm 52 about its pivot 5E. The surface of cone 55' is moved out of contact with the friction gear 64' when the arm 3 is pivoted counterclockwise about its pivot i i. In other words each point on the cones surface 55 moves upwardly to a point lying on the arc B+B of Fig. 2 so as to be free of the friction gear 54-.

Adjacent the base of the cone 55 is a cam 65 having an abrupt end or shoulder 65. The direction of rotation of the motor 6!) is such that the cone is rotated counterclockwise in the direction of the arrow as shown in Fig. 1. In the modification of Figs. 1 and 2, the cam 65 is so placed on the cone 55 that the latter makes one complete revoluti'on in timing each toasting interval. As the cone 55 rotates the cam 55 engages the end 6'! of latch lever 25 and gradually pivots it counterclockwise. The design is such that as the end 55 of cam 65 approaches the end 67 of lever 26, the hook 25 will clear the lug 32 and release the carriage !"l for upward movement under the bias of the spring 2-4; The end 57 of lever 25 is immediately returned to its uppermost position when the carriage l? moves upwardly but the cone 55 and its eam 55 has moved out of the way. The manner in which the cam 55 coacts with the lever 26 when the carriage is moved to toasting position Will be explained hereinafter.

A lever 15, is pivoted at its upper end to' the bracket 40 at H and is provided with a friction Washer 12 so that it will stay in the position in which it is placed. The lower end of lever 10 is extended forwardly at 13 so as to extend through a slot M in the base It. The extension 13 is provided with a manipulating button 15 and the base above the slot 74 isprovided' with indicia D, L and M for a purpose Which will later become apparent.

Near its upper end the lever 15 carries a bimetallic element it which extends downwardly and has its lower end ll positioned to the left of a lug F3 on lever 52 so that the lever 52 is moved to the right as the bimetallic element heats up during toasting intervals. For toasting intervals after the first the lug 18 may form a stop to limit return movement of the cone 55 and thus determine the axial point on the conical surface which will come into' engagement with the friction gear 64'.

The heaters 25 and the electric motor 55 are electrically connected to' spaced contacts insulatedly carried by the plate H5 and adapted to be bridged by the bridgingcontact 8! insulatedly carried on a spring arm attached to one of the lugs 2i so that the heaters 26 and motor 60 are simultaneously energized when the carriage I! is moved to its lower position and simultaneously deenrgized when it is released for upward movement. The motor 65 may be controlled by a separate manualswitch, if desired, as will appear hereinafter.

The electric motor 68 is preferably of the type which stops quickly after being deenergized so thatit will not overrun. In any event, the cone 55- is moved away from the gear 64 as soon as the latch arm 25 is actuated to release the carria'ge for upward movement.

In the modification of Fig. 3, the cone 55 is designed to move only a part of a revolution during each timing interval and to be returned to its original starting position at the termination of each toasting interval. For that purpose a stop pin 85 projects from the lug it of arm 52 and a light torsion spring 86 is biased to rotate the cone 55 clockwise so as to bring the shoulder .65 or cam 65 against the pin 85 when the surface of the cone 55 is moved out of engagement with the friction gear 64.

Operation In the position shown in Figs. 1 and 2 the toaster is set for making light toast, the lever l0 being positioned to the right beneath the indicia L. The lower end 11 of bimetal 16 will be positioned close to the lug 18 of lever 52.

Bread is inserted into the slots [3 so as to rest on the bread carriers (not shown) between the heaters 20. The outer ends of arms 23 (not shown) are then grasped and moved to downward position which will move the carriage l1 and bread carriers to downward position against the bias of spring 24.

As the arms 23 are moved downwardly the member 48 engages the hook 41 on the lower end of rod 45 and pivots the arm 44 clockwise. Since the arm 52 is held against sto 54 by spring 53, the arm 52 and cone 55 will also be moved clockwise until the surface of the cone 55 engages the friction gear 64. The spring 50 of rod 45 will then be elongated to place the surface of the cone 55 in good frictional engagement with the friction gear 64.

In the position shown in Figs. 1 and 2 the cone 55 has been rotated from its initial starting position and the cam 65 is shown positioned upwardly. However, in its initial starting position the cam 65 is positioned downwardly. The portion of the cam 65 adjacent the shoulder 66 is positioned above the end 6'! of lever 26. As the cone 55 approaches the friction gear 64 the cam 65 engages the end 6'! of lever 26 and pivots it counterclockwise. In the meantime the lug 32 has moved below the hook 25 of lever 26. At the same time the bridging contact 8|, which is spring-biased downwardly, engages the contacts 86 and energizes the motor 60 and the heaters 26. The motor 60 will immediately begin to rotate the cone 55 counterclockwise and the cam 65 will ride on" the end 6'! of lever 26 to permit the spring 30 to move the lever 26 clockwise to bring the hook 25 above the lug 32, latching the carriage I! in toasting position.

In the position shown in Figs. 1 and 2 the timing interval started with the toaster cold and the lower end 1'! of bimetal I6 is shown free of lug 18 of lever 52. The toaster as a whole will gradually heat up from the heat of the heaters 20 as the cone 55 is slowly rotated in performing its timing action. Toward the end of the first toasting interval the lower end 1! of bimetal (6 will contact the lug 78 of lever 52 and pivot it as well as the cone 55 counterclockwise. Since the surface of the cone 55 is longitudinally curved in r the are of a circle having its center at pivot point 5| of arm 52, the surface of the cone 55 will remain in frictional contact with the gear 64. However, as the cone 55 moves to the right the radius of the surface of the cone in contact with the gear 64 becomes smaller with the result that the speed of rotation of the cone 55 is increased and that increase takes place in infinitesimal increments as the toaster temperature rises.

Eventually, the cam 65 will come into contact with the end 61 of lever 26 and pivot it counterclockwise. The parts are so designed that just before the cam 65 rides free of the end 61 of lever 26, the hook 25 will be moved from above the lug 32 permitting the carriage l1 and its associated parts to move upwardly under the bias of spring 24. The contacts 60-6! will be opened deenergizing the motor 60 and heater 26. The motor 66 being the type which stops abruptly when deenergized, the rotation of the cone 55 will cease with the end of the cam 65 adjacent the shoulder 66 positioned above the end 6'! of lever 26, it being held in that position by the light spring 56. As

the carriage I! moves upwardly the member 48 will move out of engagement with the hook 41 of rod 45 and permit the arm 44 and with it the arm 52 and cone 55 to move counterclockwise about the pivot point 4|. The surface of the cone 55 then in contact with the gear 64 will move into the dot-dash arc BB and out of contact with the gear 64.

The operation for toasting cycles after the first is substantially the same as that described above except that the bimetal 16 may not have cooled sufiieiently to move its lower end H far enough to the left to prevent the lug 18 from contacting it at the initiation of the next toasting interval. Under such circumstances the end 11 of bimetal 16 will form a stop to predetermine the axial point on the surface of the cone 55 which will contact the gear 64 and thus predetermine the initial speed of rotation of the cone 55. In any event, the bimetal 16 is so designed as to compensate for rises in toaster temperature regardless of how fast the toaster is successively operated.

If medium or dark toast is desired the handle 15 is moved to the left to the proper position. That will pivot the lever 10 clockwise so as to move the lower end 1'! of bimetal 16 away from the lug I8 and prolong the time it takes the lower end 17 of bimetal 16 to contact lug 18 and thus prolong the toasting interval and cook the toast to a browner color.

It is to be noted that the manual adjustment is superimposed upon the thermostatic control for the timed interval.

In the modification of Fig. 3 the cone 55 rotates less than a complete revolution in timing toasting intervals and is returned to its initial position at the termination of toasting intervals. As is obvious, the gear ratio must be changed to provide for the decrease in the angle of rotation of the cone as it performs its timing action.

At the initiation of toasting intervals the cone 55 is always in the position shown in Fig. 3 with the shoulder 66 of cam in contact with the stop pin 85. When the arms 23 are moved downwardly, the cone 55 is moved into contact with the friction gear 64 and the motor 69 and heaters 26 are energized as described in the operation of the modification of Figs. 1 and 2. However, the latch arm 26 is operated in a slightly different manner.

As the arms 23 are moved downwardly the lug 32 engages the cam surface 3i of lever 26 and moves it counterclockwise to permit the lug 32 to move beneath the hook 25 at which time the latch arm 26 moves to latching position with its end 6'! in a position to be contacted by cam 65 when the cone 55 is rotated in performing its timing action.

The thermal element [6 and the manual adjustment operate to speed up the timing operation as in the first modification.

The cam 65 contacts the end 61 of lever I! to release the carriage I! for upward movement as in the first modification, except that the cone 55 is immediately returned to its original starting position by spring 86 when the surface of the cone moves out of frictional contact with the gear 64.

While the motor 66 has been shown and described as electrically connected to the contacts 66 so as to be simultaneously energized with the heaters 29 when the carriage I! is moved to toasting position, a separate manual switch may be provided for controlling the motor or it may rotate continuously as long as the toaster is plugged into an electrical outlet.

pivoted adjacent one end thereof and having said first arm pivoted thereto and operable upon pivotal movement thereof to move said gears into and out of contact with each other, said carriagemovement actuated means coacting with said second arm to move said gears into contact with each other when said carriage is moved to toasting position and to move them out of contact with each other when said carriage is moved to receiving position.

17. A toaster according to claim 16 including a bimetallic element responsive to changes in toaster temperature having a free end engageable with said first arm and operable to move the point of contact between said gears toward the apex of said cone upon rises in toaster temperature to increase the speed ratio between said gears with rises in toaster temperature.

10 18. A toaster according to claim 17 including manually actuatable means operable to move the free ends of said bimetallic element toward and away from said first arm to further vary the speed ratio between said gears.

RICHARD H. SMITH.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,763,509 Gates June 10, 1930 1,987,703 ONeill Jan. 15, 1935 2,347,611 Purpura Apr, 25, 1944 2,378,073 Felver et a1 June 12, 1945 2,567,075 Lindberg Sept. 4, 1951 2,6093% Stanton Sept. 2, 1952 2,621,584 Palmer Dec. 16, 1952 

